Conventionally, a map display device retrieving and displaying a map including a desired entity using a phone number is, for instance, applied to an in-vehicle navigation system for designating a destination. Namely, when a user inputs to the navigation system a phone number corresponding to a given entity that the user hopes to visit, a map surrounding the given entity can be shown on a display of the navigation system. Further, on the display, the given entity is shown in a center with a cursor pointing the given entity. Here, manipulating a destination-setting switch starts route guidance that guides the vehicle to the destination.
The map display device memorizes phone numbers, names, and position information of entities corresponding to the phone numbers. When a phone number is inputted, only a phone number that entirely accords with the inputted phone number can be retrieved. When the phone number that accords with the inputted phone number cannot be found, the device displays a representative point (e.g., a central area) of an area corresponding to an area code of the inputted phone number.
For instance, as occasionally seen in USA, an area code of a phone number is sometimes changed while the digits excluding the area code are not changed. In this case, displaying a map including a relevant entity cannot be achieved.